Middle Eocene Clay from Goset Abu Khashier: Geological Assessment. (introduction)

Clay bricks are traditionally made by shaping, drying and firing a mixture of clay and sand to a temperature in the range of 900–1100 °C. (Jackson, 1984) The ceramic properties of clay bricks are primarily determined by the mineralogical composition of raw clay and fired clay bricks. (Janos, 1971; Galal et al., 1985)

Abbuoda (1991) and Kamel etal (1995) studied the Middle Eocene clay deposits, in east Beni Mazarand in east Maghagha, El-Minia, Egypt. They recommended that these clay deposits were suitable for the manufacturing of clay bricks (Abbuoda, 1991; Kamel et al., 1995). The physic-ceramic properties of the Qarara Formation clay deposits in El-Mohasham area, Middle Eocene, Middle Egypt, El-Minia were investigated (Othman et al., 2003).The results obtained indicated that the deposits consist of low grade clay that can produce heavy bricks with relatively low mechanical properties. This limits the utilization of the Qarara Formation clay in the field of clay brick manufacture (Abdel Ghafour, 1995; Ramez andRamchandran, 1993). Hence, much effort must be conducted to find suitable additives that must be added to the Qarara Formation clay to improve the mechanical properties of clay brick.

After the innovation of high performance concrete, traditional clay bricks no longer satisfy the requirements of modern, sustainable building technology, because of its heavy weight and limited thermal insulation properties (Borieset al., 2014). Many additives have been added to clay to improve certain properties of clay bricks (e.g. reducing brick weight and increasing its thermal insulation ability). According to Chiang et al. (2009), the amount of brick inner pores is a controlling factor. The nature and amount of the additives have a direct impact on the physical properties of the bricks. Lightweight bricks were usually manufactured by adding combustibles as pore forming agents and agricultural wastes (e.g. corncob (Nkayem et al., 2016), seeds (Saiah et al., 2010), grass (Demir,2008), olive mill solid residue (La Rubia-García et al., 2012), sunflower seed shell (Banhidi and Gomze, 2008), rice husk (Chiang et al., 2009),rice husk ash (Sutas et al., 2012) and rice peel (Banhidi and Gomze,2008)) as well as industrial wastes (e.g. sawdust (Demir, 2008), biogases (Eliche-Quesada et al., 2011), kraft pulp residues (Demir et al., 2005),recycled paper processing residues (Sutcu and Akkurt, 2009), polystyrene(Veiseh and Yousefi, 2003) and sewage sludge (Weng et al.,2003)). It is necessary to find a compromise between its thermal and mechanical properties in order to produce a good quality lightweight brick (Bories et al., 2014).

DWTS is a waste of drinking water treatment industry that uses alum coagulant in clarification of raw water (Goosens, 1996). The amount of DWTS reaches about 5 wt% of the total untreated water quantity (Vaebi and Batebi, 2001). DWTS composes of inorganic substances (e.g. silica, aluminum and iron hydroxides) and organic substances (Miroslav, 2008). The common practice in handling with DWTS in developing countries is disposing it to the nearest water stream. This practice has an adverse impact on the environment due to rising the concentrations of aluminum and heavy metals in raw water (Prakhar and Arup, 1998). The problem of DWTS disposal can be resolved by reusing DWTS as an additive in brick making (Elangoven and Subramanian, 2011; Hegazy et al., 2012; Anyakora, 2013).

The aim of this work is to study the physico-ceramic properties of bricks that were made from the Goset Abu Khashier clay, replaced by 15–60wt% of DWTS and fired at 700–1000 °C as well as the determination of crystalline phases composition of bricks by XRD, FTIR and SEM techniques. Other works (Elangoven and Subramanian, 2011; Hegazy etal., 2012 and Anyakora, 2013) measured only the ceramic properties of fired bricks without analyzing fired bricks. In the present study the DWTS addition will be raised to 60% and the ceramic properties of fired bricks will be aided and explained by XRD, FTIR and SEM analyses of fired bricks.